O'Donnell Siobhan, Cranney Ann, Horsley Tanya, Weiler Hope A, Atkinson Stephanie A, Hanley David A, Ooi Daylily S, Ward Leanne, Barrowman Nick, Fang Manchun, Sampson Margaret, Tsertsvadze Alexander, Yazdi Fatemeh
Clinical Epidemiology Program, Ottawa Health Research Institute, Ottawa, Canada.
Am J Clin Nutr. 2008 Dec;88(6):1528-34. doi: 10.3945/ajcn.2008.26415.
Many residents of the United States and Canada depend on dietary sources of vitamin D to help maintain vitamin D status. Because few natural food sources contain vitamin D, fortified foods may be required.
We aimed to determine the effects of vitamin D-fortified foods on serum 25-hydroxyvitamin D [25(OH)D] concentrations.
We searched MEDLINE (1966 to June Week 3 2006), Embase, CINAHL, AMED, Biological Abstracts, and the Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs) comparing vitamin D-fortified foods with a control and reporting serum 25(OH)D concentrations. Two reviewers independently determined study eligibility, assessed trial quality, and extracted relevant data. Disagreements were resolved by consensus. Meta-analyses of absolute mean change in 25(OH)D were conducted by using a random-effects model, with evaluation of heterogeneity.
Nine RCTs (n = 889 subjects) were included, of which 8 consistently showed a significant beneficial effect of food fortification on 25(OH)D concentrations. Although 7 RCTs (n = 585 subjects) potentially were meta-analyzable, we were unable to combine the overall results because of significant heterogeneity. The individual treatment effects ranged from 14.5 (95% CIs: 10.6, 18.4) nmol/L to 34.5 (17.64, 51.36) nmol/L (3.4-25 microg vitamin D/d). Subgroup analyses showed a reduction in heterogeneity and significant treatment effect when 4 trials that used milk as the fortified food source were combined.
Most trials were small in size and inadequately reported allocation concealment, but results showed that vitamin D-fortified foods improved vitamin D status in adults.
美国和加拿大的许多居民依靠膳食来源的维生素D来维持维生素D水平。由于天然食物来源中含维生素D的很少，可能需要食用强化食品。
我们旨在确定维生素D强化食品对血清25-羟基维生素D[25(OH)D]浓度的影响。
我们检索了MEDLINE（1966年至2006年第3周）、Embase、CINAHL、AMED、生物学文摘数据库以及Cochrane对照试验中心注册库，查找比较维生素D强化食品与对照并报告血清25(OH)D浓度的随机对照试验（RCT）。两名评价员独立确定研究的合格性，评估试验质量，并提取相关数据。分歧通过协商解决。采用随机效应模型对25(OH)D的绝对平均变化进行Meta分析，并评估异质性。
纳入了9项RCT（n = 889名受试者），其中8项一致显示食品强化对25(OH)D浓度有显著有益影响。虽然7项RCT（n = 585名受试者）可能可进行Meta分析，但由于显著的异质性，我们无法合并总体结果。个体治疗效果范围为14.5（95%CI：10.6，18.4）nmol/L至34.5（17.64，51.36）nmol/L（3.4 - 25μg维生素D/天）。亚组分析显示，当将4项以牛奶作为强化食物来源的试验合并时，异质性降低且有显著的治疗效果。
大多数试验规模较小，分配隐藏情况报告不足，但结果表明维生素D强化食品改善了成年人的维生素D水平。
